Methods and Apparatus for Delivering Ocular Implants Into the Eye

ABSTRACT

A cannula for an ocular implant delivery system. In some embodiments, the cannula includes a tubular member having a curved portion, a distal opening surrounded by a distal opening surface, and a distal tip, the distal tip being adapted to be inserted into an anterior chamber of a human subject&#39;s eye, through trabecular meshwork and into Schlemm&#39;s canal of the eye, a proximal portion of the tubular member being adapted to extend from a location exterior to the eye when the distal tip is in Schlemm&#39;s canal of the eye, the cannula being further adapted to cooperate with an advancement mechanism to advance an ocular implant through the tubular member toward and through the distal opening into Schlemm&#39;s canal of the eye when the distal tip is disposed in Schlemm&#39;s canal. The invention also includes a method of deploying an ocular implant into Schlemm&#39;s canal of a human eye including the following steps: inserting a distal tip of a delivery tool within an anterior chamber of the eye through trabecular meshwork of the eye into Schlemm&#39;s canal of the eye; and advancing an ocular implant through a curved portion and a distal opening of the delivery tool to place a body portion of the ocular implant in Schlemm&#39;s canal and an inlet portion of the ocular implant in the anterior chamber.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/943,289, filed Nov. 20, 2007, and also claims the benefit of thefollowing: U.S. Provisional Application No. 61/120,222, filed Dec. 5,2008; U.S. Provisional Application No. 61/120,295, filed Dec. 5, 2008;U.S. Provisional Application No. 61/224,156, filed Jul. 9, 2009; andU.S. Provisional Application No. 61/224,158, filed Jul. 9, 2009. All ofthese applications are incorporated by reference as if fully set forthherein.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to devices that are implantedwithin the eye. More particularly, the present invention relates tosystems, devices and methods for delivering ocular implants into theeye.

BACKGROUND OF THE INVENTION

According to a draft report by The National Eye Institute (NEI) at TheUnited States National Institutes of Health (NIH), glaucoma is now theleading cause of irreversible blindness worldwide and the second leadingcause of blindness, behind cataract, in the world. Thus, the NEI draftreport concludes, “it is critical that significant emphasis andresources continue to be devoted to determining the pathophysiology andmanagement of this disease.” Glaucoma researchers have found a strongcorrelation between high intraocular pressure and glaucoma. For thisreason, eye care professionals routinely screen patients for glaucoma bymeasuring intraocular pressure using a device known as a tonometer. Manymodern tonometers make this measurement by blowing a sudden puff of airagainst the outer surface of the eye.

The eye can be conceptualized as a ball filled with fluid. There are twotypes of fluid inside the eye. The cavity behind the lens is filled witha viscous fluid known as vitreous humor. The cavities in front of thelens are filled with a fluid know as aqueous humor. Whenever a personviews an object, he or she is viewing that object through both thevitreous humor and the aqueous humor.

Whenever a person views an object, he or she is also viewing that objectthrough the cornea and the lens of the eye. In order to be transparent,the cornea and the lens can include no blood vessels. Accordingly, noblood flows through the cornea and the lens to provide nutrition tothese tissues and to remove wastes from these tissues. Instead, thesefunctions are performed by the aqueous humor. A continuous flow ofaqueous humor through the eye provides nutrition to portions of the eye(e.g., the cornea and the lens) that have no blood vessels. This flow ofaqueous humor also removes waste from these tissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of theanterior chamber of the eye through the trabecular meshwork and intoSchlemm's canal as new aqueous humor is secreted by the epithelial cellsof the ciliary body. This excess aqueous humor enters the venous bloodstream from Schlemm's canal and is carried along with the venous bloodleaving the eye.

When the natural drainage mechanisms of the eye stop functioningproperly, the pressure inside the eye begins to rise. Researchers havetheorized prolonged exposure to high intraocular pressure causes damageto the optic nerve that transmits sensory information from the eye tothe brain. This damage to the optic nerve results in loss of peripheralvision. As glaucoma progresses, more and more of the visual field islost until the patient is completely blind.

In addition to drug treatments, a variety of surgical treatments forglaucoma have been performed. For example, shunts were implanted todirect aqueous humor from the anterior chamber to the extraocular vein(Lee and Scheppens, “Aqueous-venous shunt and intraocular pressure,”Investigative Opthalmology (February 1966)). Other early glaucomatreatment implants led from the anterior chamber to a sub-conjunctivalbleb (e.g., U.S. Pat. No. 4,968,296 and U.S. Pat. No. 5,180,362). Stillothers were shunts leading from the anterior chamber to a point justinside Schlemm's canal (Spiegel et al., “Schlemm's canal implant: a newmethod to lower intraocular pressure in patients with POAG?” OphthalmicSurgery and Lasers (June 1999); U.S. Pat. No. 6,450,984; U.S. Pat. No.6,450,984).

SUMMARY OF THE INVENTION

The invention pertains to aspects of ocular implants and ocular implantdelivery systems. One aspect of the invention provides a cannula for anocular implant delivery system. In some embodiments, the cannulaincludes a tubular member having a curved portion, a distal openingsurrounded by a distal opening surface, and a distal tip, the distal tipbeing adapted to be inserted into an anterior chamber of a humansubject's eye, through trabecular meshwork and into Schlemm's canal ofthe eye, a proximal portion of the tubular member being adapted toextend from a location exterior to the eye when the distal tip is inSchlemm's canal of the eye, the cannula being further adapted tocooperate with an advancement mechanism to advance an ocular implantthrough the tubular member toward and through the distal opening intoSchlemm's canal of the eye when the distal tip is disposed in Schlemm'scanal.

In some embodiments, the cannula's tubular member also has a tongueregion extending proximally from the distal tip on one side of thetubular member, with the tongue region forming at least part of thedistal opening surface. In some embodiments the distal opening surfaceextends solely proximally from the distal tip, and the distal openingsurface may be disposed in a distal opening plane. The tubular membercurved portion may also define a curve plane, and the distal openingplane may be at an angle other than 90 degrees with respect to the curveplane.

In some embodiments of the cannula, the distal opening surface has afirst section disposed in a distal opening plane disposed at a firstsection angle between 0 degrees and 90 degrees with respect to alongitudinal axis of the tubular member at the distal opening and asecond section whose angle with respect to the longitudinal axis of thetubular member varies from an angle less than the first section angle ata distal limit of the second section to an angle greater than the firstsection angle at a proximal limit of the second section.

In other embodiments of the cannula, the distal opening surface has anedge formed from a circumferential portion of a cylindrical envelopedefined by the tubular member, the angular extent of the circumferentialportion within the cylindrical envelope increasing from the distal tipproximally to a first point, the angular extent of the circumferentialportion within the cylindrical envelope decreasing between the firstpoint and a second point proximal to the first point, the angular extentof the circumferential portion within the cylindrical envelopeincreasing to 360 degrees between the second point and a third pointproximal to the second point.

In some embodiments of the cannula, the tubular member also a secondtongue region and a stop member defining the distal opening surface.

In some embodiments, an external diameter of the tubular member at adistal end of the tubular member is less than an external diameter ofthe tubular member proximal to the distal opening. The curved portion ofthe tubular member may also have a bend angle between 105 degrees and165 degrees.

Another aspect of the invention provides an ocular implant systemincluding an ocular implant having an inlet sized and configured to bedisposed in an anterior chamber of a human subject's eye and a bodysized and configured to be disposed in Schlemm's canal of the eye, theocular implant being adapted to bend preferentially in a preferentialbending plane; and a delivery cannula comprising a tubular member with acurved portion, a distal opening surrounded by a distal opening surface,and a distal tip, the distal tip being adapted to be inserted into ananterior chamber of a human subject's eye, through trabecular meshworkand into Schlemm's canal of the eye, the tubular member being adapted toextend from a location exterior to the eye when the distal tip is inSchlemm's canal of the eye, the cannula being further adapted tocooperate with an advancement mechanism to advance the ocular implantthrough at least the curved portion of the tubular member toward andthrough the distal opening into Schlemm's canal of the eye when thedistal tip of the delivery tool is disposed in Schlemm's canal.

In some embodiments of the ocular implant system, a central axis of thecannula defines a cannula curvature plane, the ocular implant beingoriented within the cannula so that the implant preferential bendingplane is co-planar with the cannula curvature plane.

Yet another aspect of the invention provides a method of deploying anocular implant into Schlemm's canal of a human eye. The method mayinclude the following steps: inserting a distal tip of a delivery toolwithin an anterior chamber of the eye through trabecular meshwork of theeye into Schlemm's canal of the eye; and advancing an ocular implantthrough a curved portion and a distal opening of the delivery tool toplace a body portion of the ocular implant in Schlemm's canal and aninlet portion of the ocular implant in the anterior chamber.

In some embodiments, the delivery tool has a curved distal portion, theinserting step including the step of aligning the curved distal portionwith respect to Schlemm's canal so that the ocular implant is deliveredinto the center of Schlemm's canal or slightly radially inward of anouter wall of Schlemm's canal. The curved distal portion of the deliverytool may have a radius of curvature smaller than that of Schlemm'scanal.

In some embodiments, the inserting step includes the step of advancingthe distal tip into Schlemm's canal until a stop portion of a distalopening surface surrounding the distal opening engages the trabecularmeshwork. The inserting step may also include the step of depressingtrabecular meshwork and Schlemm's canal tissue with the distal tip witha distal opening surface surrounding the distal opening, the distalopening surface being disposed at an angle other than 90 degrees withrespect to a longitudinal axis of the delivery tool.

In embodiments in which the delivery tool has a distal opening surfacesurrounding the distal opening, the inserting step may include the stepof inserting less than all of the distal opening surface into Schlemm'scanal.

In some embodiments, the delivery tool has a distal opening surfacesurrounding the distal opening and the distal tip is disposed at thedistal end of a tongue. In such embodiments the inserting step mayinclude the step of inserting the tongue into Schlemm's canal. Theadvancing step may also include the step of advancing the ocular implantthrough the distal opening while a portion of the distal opening surfaceis disposed in Schlemm's canal and a portion of the distal openingsurface is disposed outside of Schlemm's canal.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a stylized perspective view depicting an exemplary ocularimplant extending from a portion of a human eye.

FIG. 2 is a perspective view showing a portion of the ocular implantshown in FIG. 1.

FIG. 3 is a perspective view illustrating a volume defined by the bodyof the ocular implant shown in FIG. 2.

FIG. 4 is a perspective view illustrating a first plane and a secondplane that both intersect an exemplary ocular implant.

FIG. 5 is an enlarged perspective view showing a portion of the ocularimplant shown in FIG. 4.

FIG. 6 is stylized representation of an exemplary medical procedure inaccordance with the present disclosure.

FIG. 7 is an enlarged plan view showing illustrating insertion of anocular implant delivery system cannula into the eye shown in theprevious figure.

FIG. 8 is a further enlarged plan view illustrating insertion of theocular implant delivery system cannula into the eye shown in theprevious figure.

FIG. 9 is an additional plan view of the eye shown in the previousfigure showing advancement of an ocular implant through the cannula intoSchlemm's canal of the eye.

FIG. 10 is an additional plan view of the eye shown in the previousfigure. In the embodiment of FIG. 10, a core that was used to positionthe ocular implant has been withdrawn.

FIG. 11 is a plan view of the eye shown in the previous figure showingthe ocular implant in Schlemm's canal after the cannula has beenwithdrawn.

FIG. 12 is a perspective view of an exemplary cannula assembly.

FIG. 13 is an enlarged perspective view showing a portion of a tubularmember of the cannula shown in the previous figure.

FIG. 14 is a plan view further illustrating the cannula assembly of FIG.12.

FIG. 15 is an enlarged plan view showing a portion of the tubular membershown in the previous figure.

FIG. 16 is a plan view further illustrating the cannula assembly of FIG.12.

FIGS. 17A and 17B are plan views further illustrating the tubular memberof the cannula assembly shown in FIG. 12.

FIGS. 18A and 18B are plan views further illustrating the tubular memberof the cannula assembly shown in FIG. 12.

FIG. 19 is a plan view illustrating an alternate embodiment of a cannulaassembly.

FIG. 20 is a stylized perspective view showing a portion of the tubularmember shown in the previous figure delivering an ocular implant intoSchlemm's canal.

FIG. 21 is a perspective view of an another embodiment of an ocularimplant delivery system cannula in accordance with this invention.

FIG. 22 is a partial sectional and perspective view showing portions ofan ocular implant delivery system into which an ocular implant has beenloaded.

FIG. 23 is an additional perspective view of the assembly shown in FIG.22 showing delivery of the ocular implant into Schlemm's canal.

FIG. 24 is an additional perspective view showing portions of theimplant and the cannula shown in FIGS. 22 and 23.

FIG. 25C is a plan view showing a cannula. FIG. 25B is a cross sectionalview of the cannula sectioned along cutting line B-B shown in FIG. 25C.FIG. 25A is an axial plan view created from the viewpoint illustrated byline A-A in FIG. 25C.

FIGS. 26A, 26B, and 26C are three orthographic views of illustrating thestructural features of an exemplary ocular implant delivery systemcannula.

FIG. 27 is an isometric view of the ocular implant delivery systemcannula illustrating a tongue of the cannula.

FIG. 28 is a schematic partial cross-sectional view showing the distaltip of an ocular implant delivery system cannula entering Schlemm'scanal.

FIG. 29 is a plan view of yet another embodiment of part an ocularimplant delivery system cannula.

FIG. 30 is a perspective view of a portion of the cannula of FIG. 29.

FIG. 31 is a partial cross-sectional view and a partial plan viewshowing an ocular implant being delivered into Schlemm's canal usingstill another embodiment of a delivery system cannula according to thisinvention.

FIG. 32 is an elevational view of a portion of the cannula of thedelivery system of FIG. 31.

FIG. 33 is a side elevational view of a portion of the cannula of FIG.32.

FIG. 34 is a further partial cross-sectional view and partialperspective view showing the ocular implant being delivered intoSchlemm's canal using a delivery system cannula according to theembodiment of FIG. 31.

FIG. 35 is a partial cross-sectional view and a partial plan view of animplant in place within Schlemm's canal after delivery.

FIGS. 36A and 36B are partial section and perspective views illustratinginsertion of the distal tip of an ocular implant delivery system cannulainto Schlemm's canal.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

Apparatus and methods in accordance with the present detaileddescription may be used to deliver an ocular implant into a subject'seye and to place distal portion of an ocular implant in Schlemm's canalof an eye. FIG. 1 is a stylized perspective view depicting a portion ofa human eye 20. Eye 20 can be conceptualized as a fluid filled ballhaving two chambers. Sclera 22 of eye 20 surrounds a posterior chamber24 filled with a viscous fluid known as vitreous humor. Cornea 26 of eye20 encloses an anterior chamber 30 that is filled with a fluid know asaqueous humor. The cornea 26 meets the sclera 22 at a limbus 28 of eye20. A lens 32 of eye 20 is located between anterior chamber 30 andposterior chamber 24. Lens 32 is held in place by a number of ciliaryzonules 34.

Whenever a person views an object, he or she is viewing that objectthrough the cornea, the aqueous humor, and the lens of the eye. In orderto be transparent, the cornea and the lens can include no blood vessels.Accordingly, no blood flows through the cornea and the lens to providenutrition to these tissues and to remove wastes from these tissues.Instead, these functions are performed by the aqueous humor. Acontinuous flow of aqueous humor through the eye provides nutrition toportions of the eye (e.g., the cornea and the lens) that have no bloodvessels. This flow of aqueous humor also removes waste from thesetissues.

Aqueous humor is produced by an organ known as the ciliary body. Theciliary body includes epithelial cells that continuously secrete aqueoushumor. In a healthy eye, a stream of aqueous humor flows out of the eyeas new aqueous humor is secreted by the epithelial cells of the ciliarybody. This excess aqueous humor enters the blood stream and is carriedaway by venous blood leaving the eye.

In a healthy eye, aqueous humor flows out of the anterior chamber 30through the trabecular meshwork 36 and into Schlemm's canal 38, locatedat the outer edge of the iris 42. Aqueous humor exits Schlemm's canal 38by flowing through a number of outlets 40. After leaving Schlemm's canal38, aqueous humor is absorbed into the venous blood stream.

In FIG. 1, an ocular implant 100 is disposed in Schlemm's canal 38 ofeye 20. Ocular implant 100 has a body 102 including a plurality oftissue supporting frames 104 and a plurality of spines 106. Body 102also includes a first edge 120 and a second edge 122 that define a firstopening 124. First opening 124 is formed as a slot and fluidlycommunicates with an elongate channel 126 defined by an inner surface128 of body 102. With reference to FIG. 1, it will be appreciated thatfirst opening 124 is disposed on an outer side 130 of body 102.Accordingly, channel 126 opens in a radially outward direction 132 viafirst opening 124.

Ocular implant 100 may be inserted into Schlemm's canal of a human eyeto facilitate the flow of aqueous humor out of the anterior chamber.This flow may include axial flow along Schlemm's canal, flow from theanterior chamber into Schlemm's canal, and flow leaving Schlemm's canalvia outlets communicating with Schlemm's canal. When in place within theeye, ocular implant 100 will support trabecular mesh tissue andSchlemm's canal tissue and will provide for improved communicationbetween the anterior chamber and Schlemm's canal (via the trabecularmeshwork) and between pockets or compartments along Schlemm's canal. Asshown in FIG. 1, the implant is preferably oriented so that the firstopening 124 is disposed radially outwardly within Schlemm's canal.

FIG. 2 is an enlarged perspective view showing a portion of ocularimplant 100 shown in the previous figure. Ocular implant 100 has a body102 that extends along a generally curved longitudinal axis 134. Body102 has a plurality of tissue supporting frames 104 and a plurality ofspines 106. As shown in FIG. 2, these spines 106 and frames 104 arearranged in a repeating AB pattern in which each A is a tissuesupporting frame and each B is a spine. In the embodiment of FIG. 2, onespine extends between each adjacent pair of frames 104.

For example, frame 136 of ocular implant 100 is disposed between a firstspine 140 and a second spine 142. Frame 136 is formed as a first strut144 that extends between first spine 140 and second spine 142 and asecond strut 146 extending between first spine 140 and second spine 142.In the exemplary embodiment of FIG. 2, struts 144 and 146 each undulatesin a circumferential direction as it extends longitudinally betweenfirst spine 140 and second spine 142.

In the embodiment of FIG. 2, body 102 has a longitudinal radius ofcurvature 150 and a lateral radius of curvature 148. Body 102 of ocularimplant 100 includes a first edge 120 and a second edge 122 that definefirst opening 124. First opening 124 fluidly communicates with anelongate channel 126 defined by an inner surface 128 of body 102. Asecond opening 138 is defined by a second edge 122A of first strut 144and a second edge 122B of second strut 146. First opening 124, secondopening 138 and additional openings defined by ocular implant 100 allowaqueous humor to flow laterally across and/or laterally through ocularimplant 100. The outer surfaces of body 102 define a volume 152.

FIG. 3 is an additional perspective view showing volume 152 defined bythe body of the ocular implant shown in the previous figure. Withreference to FIG. 3, it will be appreciated that volume 152 extendsalong a generally curved longitudinal axis 134. Volume 152 has alongitudinal radius 150, a lateral radius 148, and a generally circularlateral cross section 153.

FIG. 4 is a perspective view showing a first plane 154 and a secondplane 155 that both intersect ocular implant 100. In FIG. 4, first plane154 is delineated with hatch marks. With reference to FIG. 4, it will beappreciated that spines 106 of body 102 are generally aligned with oneanother and that first plane 154 intersects all spines 106 shown in FIG.4. In the embodiment of FIG. 4, body 102 of ocular implant 100 isgenerally symmetric about first plane 154.

In the embodiment of FIG. 4, the flexibility of body 102 is at a maximumwhen body 102 is bending along first plane 154, and body 102 has lessflexibility when bending along a plane other than first plane 154 (e.g.,a plane that intersects first plane 154). Accordingly, first plane 154may be generally referred to as a plane of preferential bending. In theembodiment shown in FIG. 4, for example, body 102 has a secondflexibility when bending along second plane 155 that is less than thefirst flexibility that body 102 has when bending along first plane 154.

Stated another way, in the embodiment of FIG. 4, the bending modulus ofbody 102 is at a minimum when body 102 is bent along first plane 154.Body 102 has a first bending modulus when bent along first plane 154 anda greater bending modulus when bent along a plane other than first plane154 (e.g., a plane that intersects first plane 154). For example, in theembodiment shown in FIG. 4, body 102 has a second bending modulus whenbent along second plane 155 that is greater than the first bendingmodulus that body 102 has when bent along first plane 154.

FIG. 5 is an enlarged perspective view showing a portion of ocularimplant 100 shown in the previous figure. In the exemplary embodiment ofFIG. 5, a bending moment M is being applied to body 102 of ocularimplant 100. Bending moment M acts about a first axis 156 that isgenerally orthogonal to first plane 154. A second axis 158 and a thirdaxis 160 are also shown in FIG. 5. Second axis 158 is generallyperpendicular to first axis 156. Third axis 160 is skewed relative tofirst axis 156.

In the embodiment of FIG. 5, the flexibility of body 102 is at a maximumwhen body 102 is bent by a moment acting about first axis 156, and body102 has less flexibility when bent by a moment acting about an axisother than first axis 156 (e.g., second axis 158 and third axis 160).Stated another way, the bending modulus of body 102 is at a minimum whenbody 102 is bent by a moment acting about first axis 156, and body 102has a greater bending modulus when bent by a moment acting about an axisother than first axis 156 (e.g., second axis 158 and third axis 160).

FIG. 6 is stylized representation of an exemplary medical procedure inaccordance with this detailed description. In the exemplary procedure ofFIG. 6, a physician is treating an eye 20 of a patient 620. In theexemplary procedure of FIG. 6, a physician is holding a delivery systemin his or her right hand RH. The physician's left hand (not shown) maybe used to hold the handle H of a gonio lens 628. It will be appreciatedthat some physician's may prefer holding the delivery system handle inthe left hand and the gonio lens handle H in the right hand RH.

During the exemplary procedure illustrated in FIG. 6, the physician mayview the interior of the anterior chamber using a microscope 626 andgonio lens 628. Detail A of FIG. 6 is a stylized simulation of the imageviewed by the physician. A distal portion of a cannula is visible inDetail A. The distal end of the cannula is positioned near Schlemm'scanal SC of eye 22. A shadow-like line indicates the location ofSchlemm's canal SC which is lying under various tissue (e.g., thetrabecular meshwork) that surround the anterior chamber.

FIG. 7 is an enlarged plan view showing a portion of the face shown inthe previous figure. In the embodiment of FIG. 7, cannula 708 extendsthrough a cornea of eye 20 so that the distal end of cannula 708 isdisposed in the anterior chamber of eye 20. With reference to FIG. 7, itwill be appreciated that the distal tip of cannula 708 is positionednear the trabecular mesh 36 of eye 20.

FIG. 8 is a further enlarged plan view illustrating a portion of eye 20shown in the previous figure. In the embodiment of FIG. 8, the distaltip of cannula 708 has pierced through trabecular mesh 36. The distaltip of cannula 708 has also pierced the wall of Schlemm's canal 38 sothat a distal opening 758 of cannula 708 is disposed in fluidcommunication with Schlemm's canal 38. In this embodiment, cannula 708is a rigid curved tube that has a sharp portion at its distal end nearthe exit port 758. In some embodiments, cannula 708 is curved to achievesubstantially tangential entry into Schlemm's canal 38.

FIG. 9 is an additional plan view of eye 20 shown in the previousfigure. In the embodiment of FIG. 9, an ocular implant 900 has beenadvanced through distal opening 758 of cannula 708 and into Schlemm'scanal 38 of eye 20. With reference to FIG. 9, it will be appreciatedthat ocular implant 900 is disposed about a core 754 which is movablewith ocular implant 900 within cannula 708 as part of an implantadvancement mechanism. Core 754 and cannula 708 are part of a deliverysystem that may be used to deliver ocular implant 900 into Schlemm'scanal of eye 20.

Among other functions, one particular function of core 754 is to blockthe openings formed in ocular implant 900 so as to minimize interferencebetween the implant and tissue within Schlemm's canal 38 as the implantis advanced. The delivery system's advancement mechanism may alsoinclude a push tube (not shown) for selectively applying distallydirected forces to the proximal end of ocular implant 900. Core 754 mayextend proximally into the push tube. A handheld actuator (not shown)may be used to advance the push tube, the core 754 and the ocularimplant 900. The handheld actuator may also be used to provide relativemotion between the push tube and the core 754. In the embodiment of FIG.9, ocular implant 900 has a blunt distal end 902 for avoiding damage toocular tissue. In other embodiments, the blunt distal end may beprovided at least in part by core 754. Further details of aspects ofocular implant delivery systems suitable for use with implants andcannulas of this invention may be found in U.S. application Ser. No.11/943,289, filed Nov. 20, 2007; U.S. Application No. 12/398,847, filedMar. 5, 2009; U.S. Provisional Application No. 61/224,156, filed Jul. 9,2009; and U.S. Provisional Application No. 61/224,158, filed Jul. 9,2009; the disclosures of which are incorporated herein by reference.

FIG. 10 is an additional plan view of eye 20 shown in the previousfigure. In the embodiment of FIG. 10, core 754 has been withdrawn fromocular implant 900. A hand held actuator (not shown) may be used toapply a proximal force to the core to withdraw the core proximally fromthe ocular implant 900 while a push tube (not shown) applies a distallydirected force to hold ocular implant 900 in place. The core, the pushtube, and the cannula 708 may then be withdrawn from the eye, leavingthe implant in Schlemm's canal with its proximal inlet end within theanterior chamber of eye 20.

FIG. 11 is a plan view of eye 20 after cannula 708 has been withdrawnleaving an inlet portion 904 of ocular implant 900 in the anteriorchamber and the remainder of implant 900 in Schlemm's canal. Thepresence of ocular implant 900 in Schlemm's canal may facilitate theflow of aqueous humor out of the anterior chamber. This flow may includeaxial flow along Schlemm's canal, flow from the anterior chamber intoSchlemm's canal, and flow leaving Schlemm's canal via outletscommunicating with Schlemm's canal. When in place within the eye, ocularimplant 900 will support trabecular mesh tissue and Schlemm's canaltissue and will provide for improved communication between the anteriorchamber and Schlemm's canal (via the trabecular meshwork) and betweenpockets or compartments along Schlemm's canal.

FIG. 12 is a perspective view of an exemplary cannula assembly 1200.Cannula assembly 1200 comprises a tubular member 1202 that is fixed to ahub 1204. Tubular member 1202 defines a proximal opening 1206, a distalopening 1158, and a lumen 1208 that extends between proximal opening1206 and distal opening 1158. Tubular member 1202 also comprises aproximal portion 1210, a distal portion 1212, and a bent portion 1214disposed between proximal portion 1210 and distal portion 1212.

FIG. 13 is an enlarged perspective view showing a portion of tubularmember 1202 shown in the previous figure. With reference to FIG. 13, itwill be appreciated that tubular member 1202 comprises a beveled distaltip 1216 having a distal opening surface 1218. In the exemplaryembodiment of FIG. 13, beveled distal tip 1216 defines a distal opening1158 having a generally elliptical shape. A major axis 1220 and a minoraxis 1222 of distal opening 1158 are illustrated using dashed lines inFIG. 13. For purposes of illustration, major axis 1220 and minor axis1222 each extend beyond distal opening 1158 in FIG. 13.

In the exemplary embodiment of FIG. 13, major axis 1220 and minor axis1222 define an exit plane 1224. Distal opening 1158 opens in a directionD that is orthogonal to exit plane 1224. Direction D is illustratedusing an arrow in FIG. 13. In some useful embodiments, an imaginary linerepresenting direction D intersects the cornea of the eye when the whenthe tubular member is extending through the cornea and the distalopening is fluidly communicating with Schlemm's canal of the eye.

FIG. 14 is a plan view further illustrating cannula assembly 1200. Withreference to FIG. 14, it will be appreciated that tubular member 1202 ofcannula assembly 1200 comprises a proximal portion 1210, a distalportion 1212, and a bent portion. 1214 disposed between proximal portion1220 and distal portion 1222. In the exemplary embodiment of FIG. 14, ahub 1204 is fixed to proximal portion 1210 of tubular member 1202. Withreference to FIG. 14, it will be appreciated that tubular member 1202has a central axis 1226. Central axis 1226 of FIG. 14 has a curvedportion and straight portions. In FIG. 14, a bend angle BA is shownextending between a first straight portion of central axis 1226 and asecond straight portion of central axis 1226.

In some useful embodiments, bent portion 1214 of tubular member 1202 isdimensioned to achieve substantially tangential entry into Schlemm'scanal of a human eye. In these useful embodiments, bent portion 1214 mayhave a radius of curvature between about 0.05 inches and about 0.3inches, and an angular span between about 105 degrees and about 165degrees. In one exemplary embodiment, bent portion 1214 has a bendradius of about 0.125 inches (measured to the tube centerline) and anangular span of about 132.5 degrees. In this exemplary embodiment,distal portion 1212 may have a length of about 0.044 inches and proximalportion 1210 may have a length of about 0.727 inches.

FIG. 15 is an enlarged plan view showing a portion of tubular member1202 shown in the previous figure. With reference to FIG. 15, it will beappreciated that tubular member 1202 has a central axis 1226 defining abend plane 1228. Central axis 1226 of FIG. 15 has a curved portion andstraight portions. Tubular member 1202 of FIG. 15 also comprises abeveled distal tip 1216 having a distal opening surface 1228. In theexemplary embodiment of FIG. 15, beveled distal tip 1216 defines adistal opening 1158 having a generally elliptical shape. A major axis1220 and a minor axis 1222 of distal opening 1158 are illustrated usingdashed lines in FIG. 15.

For purposes of illustration, major axis 1220 and minor axis 1222 eachextend beyond distal opening 1158 in FIG. 15. In the exemplaryembodiment of FIG. 15, major axis 1220 and minor axis 1222 define anexit plane 1224. In FIG. 15, exit plane 1224 is shown intersecting bendplane 1228. With reference to FIG. 15, it will be appreciated that exitplane 1224 is generally skewed relative to bend plane 1228. That is, theplane 1222 of distal opening surface 1228 meets plane 1228 of thecannula curve at an angle other than 90 degrees.

FIG. 16 is a plan view further illustrating cannula assembly 1200. Withreference to FIG. 16, it will be appreciated that tubular member 1202 ofcannula assembly 1200 comprises a first portion 1230 having a firstdiameter DA, a second portion 1232 having a second diameter DB, and atapered portion 1234 disposed between first portion 1230 and secondportion 1232.

In the exemplary embodiment of FIG. 16, first diameter DA is greaterthan second diameter DB, and tapered portion 1234 transitions betweenfirst diameter DA and second diameter DB. In some useful embodiments,tapered portion 1234 has an average taper ratio between about 0.01 andabout 0.12. In one exemplary embodiment, tapered portion 1234 has anaverage taper ratio of about 0.068.

Tubular member 1202 defines a proximal opening (not shown), a distalopening 1158, and a lumen 1208 that extends between the proximal openingand the distal opening. In the exemplary embodiment of FIG. 16, lumen1208 has a generally circular cross-sectional shape. In some usefulembodiments, lumen 1208 has a diameter that is substantially uniformalong the length of tubular member 1202. This configuration reduces thelikelihood that an ocular implant advanced through lumen 1208 willbecome hung up during delivery through the lumen.

In some useful embodiments, second diameter DB is dimensioned so thatdistal opening 1158 can be placed in fluid communication with Schlemm'scanal of a human eye. Also in some useful embodiments, first diameter DAis dimensioned to provide a desirable level of structural support whentubular member 1202 is advance through the cornea of a human eye and thedistal end of beveled tip 1216 is inserted into Schlemm's canal.

In some useful embodiments first diameter DA is between about 0.010 andabout 0.030 inches and second diameter DB is between about 0.005 andabout 0.020. In one exemplary embodiment, first diameter DA is about0.018 inches, second diameter DB is about 0.016, and the diameter oflumen 1208 is about 0.0135 inches. With reference to FIG. 16, it will beappreciated that tubular member 1202 comprises a bent portion 1214. Inthe exemplary embodiment of FIG. 16, tapered portion 1234 is extendsalong a portion of bent portion 1214 of tubular member 1202.

FIG. 17A and FIG. 17B are plan views further illustrating tubular member1202 of cannula assembly 1200. With reference to FIG. 17A, it will beappreciated that tubular member 1202 comprises a beveled distal tip 1216having a distal opening surface 1218. In the exemplary embodiment ofFIG. 17A, beveled distal tip 1216 defines a distal opening 1158 having agenerally elliptical shape. A major axis 1220 and a minor axis 1222 ofdistal opening 1158 are illustrated using dashed lines in FIG. 17A. Forpurposes of illustration, major axis 1220 and minor axis 1222 eachextend beyond distal opening 158 in FIG. 17A.

FIG. 17B is an additional plan view showing the portion of tubularmember 1202 shown in FIG. 17A. FIG. 17B is taken from a viewpoint thatis generally orthogonal to the viewpoint used to create FIG. 17A. Withreference to FIG. 17B, it will be appreciated that tubular member 1202has a central axis 1226 that includes both straight portions and curvedportions.

Major axis 1220 of distal opening 1158 and central axis 1226 of tubularmember 1202 define a pitch angle PA of beveled distal tip 1216. In someuseful embodiments, pitch angle PA is steep enough to tent open tissue(e.g., trabecular mesh and the wall of Schlemm's canal) when the distalend of beveled tip 1216 is inserted into Schlemm's canal. Also in someuseful embodiments, pitch angle PA is shallow enough to prevent tearingor cutting of tissue when the distal end of beveled tip 1216 is insertedinto Schlemm's canal. In some useful embodiments, pitch angle PA isbetween about 5 degrees and about 35 degrees. In some particularlyuseful embodiments, pitch angle PA is greater than about 15 degrees andless than about 25 degrees. In one exemplary embodiment, pitch angle PAis about 20 degrees.

FIG. 18A and FIG. 18B are plan views further illustrating tubular member1202 of cannula assembly 1200. With reference to FIG. 18B, it will beappreciated that tubular member 1202 has a central axis 1226 defining abend plane 1228. Central axis 1226 of FIG. 18B has a curved portion andstraight portions. In the embodiment of FIG. 18B, tubular member 1202also comprises a beveled distal tip 1216 having a distal opening surface1218. In the exemplary embodiment of FIG. 18B, beveled distal tip 1216defines a distal opening 1158 having a generally elliptical shape. Amajor axis 1220 and a minor axis 1222 of distal opening 1158 areillustrated using dashed lines in FIG. 18B.

FIG. 18A is an axial plan view showing tubular member 1202 and distalopening surface 1218. FIG. 18A is taken from a viewpoint that isgenerally orthogonal to the viewpoint used to create FIG. 18B. Bendplane 1228, major axis 1220 and minor axis 1222 are illustrated usingdashed lines in FIG. 18A. With reference to FIG. 18A, it will beappreciated that minor axis 1222 of distal opening 1158 and bend plane1228 define a roll angle RA.

In some useful embodiments, roll angle RA is selected so that aphysician using the cannula assembly can see distal opening 1158 whenthe tubular member 1202 is extending through the cornea of a human eyeand the distal end of beveled distal tip 1216 is inserted into Schlemm'scanal. In other words, the plane of distal opening surface 1218 meetsbend plane 1228 at an angle other than 90 degrees. Also in some usefulembodiments, roll angle RA is selected so that distal end of beveleddistal tip 1216 is the first part of tubular member 1202 to touch tissuewhen the tubular member 1202 is extending through the cornea of a humaneye and the distal end of beveled distal tip 1216 is inserted intoSchlemm's canal.

Additionally, roll angle RA may be selected so that an ocular implanttravels over the point of beveled distal tip 1216 as the ocular implantis advanced out of distal opening 1158 and into Schlemm's canal. In someuseful embodiments, roll angle RA is greater than about 100 degrees andless than about 110 degrees. In one exemplary embodiment, roll angle RAis about 105 degrees.

FIG. 19 is a plan view illustrating an alternate exemplary embodiment ofan ocular implant delivery system cannula assembly. With reference toFIG. 19, it will be appreciated that tubular member 1902 of cannulaassembly 1900 comprises a first portion 1908 having a first diameter DAand a second portion 1910 having a second diameter DB. A step 1912 isdisposed between first portion 1908 and second portion 1910. In someuseful embodiments, second diameter DB is dimensioned so that distalopening 1904 can be placed in fluid communication with Schlemm's canalof a human eye. Also in some useful embodiments, first diameter DA isdimensioned to provide a desirable level of structural support whentubular member 1902 is advance through the cornea of a human eye and thedistal end of beveled distal tip 1906 is inserted into Schlemm's canal.In some useful embodiments first diameter DA is between about 0.010 andabout 0.030 inches and second diameter DB is between about 0.005 andabout 0.020. In one exemplary embodiment, first diameter DA is about0.018 inches, second diameter DB is about 0.016, and the diameter of theinner lumen of tubular member 1902 is about 0.0135 inches.

FIG. 20 is a stylized perspective view showing a portion of tubularmember 1908 shown in the previous figure. In FIG. 20, an ocular implant900 is shown extending through distal opening 1904 of tubular member1908 and into Schlemm's canal 38 of an eye. The distal end of beveleddistal tip 1906 has penetrated the trabecular mesh 36 of the eye, anddistal opening 1904 is in fluid communication with Schlemm's canal 38.In the embodiment of FIG. 20, ocular implant 900 is oriented so that thelongitudinal channel of ocular implant 900 opens radially outward.

FIG. 21 is a perspective view of a cannula 2108 in accordance with thepresent detailed description. Cannula 2108 of FIG. 21 comprises agenerally tubular member 2162 having a central axis 2164. Generallytubular member 2162 of FIG. 21 comprises a proximal portion 2166, adistal end 2168, and a distal portion 2170 extending between distal end2168 and proximal portion 2166. A distal opening surface 2167 surroundsa distal opening 2169.

In the exemplary embodiment of FIG. 21, proximal portion 2166 of cannula2108 is substantially straight, distal portion 2170 of cannula 2108 iscurved, and central axis 2164 defines a curvature plane 2172. Curvatureplane 2172 may be referred to as a plane of curvature. With reference toFIG. 21, it will be appreciated that curvature plane 2172 dividescannula 2108 into a first portion PA and a second portion PB. In theexemplary embodiment of FIG. 21, second portion PB is substantially amirror image of first portion PA. In FIG. 21, distal portion 2170 isshown extending between distal end 2168 and proximal portion 2166 withno intervening elements. In the exemplary embodiment of FIG. 21, distalportion 2170 is curved along its entire length.

An exemplary method in accordance with this detailed description mayinclude the step of advancing the distal end 2168 of cannula 2108through the cornea of a human eye so that distal end 2168 is disposed inthe anterior chamber of the eye. Cannula 2108 may then be used to accessSchlemm's canal of the eye, for example, by piercing the wall ofSchlemm's canal with the distal end 2168 of cannula 108. Distal opening2169 of cannula 2108 may be placed in fluid communication with a lumendefined by Schlemm's canal. The ocular implant may be advanced out of adistal port of the cannula and into Schlemm's canal.

FIG. 22 is a perspective view of an assembly 2182 including cannula 2108shown in the previous figure. For purposes of illustration, cannula 2108is cross-sectionally illustrated in FIG. 22. In FIG. 22, an ocularimplant 100 can be seen resting in a lumen 2184 defined by cannula 2108.In the exemplary embodiment of FIG. 22, ocular implant 100 is disposedabout a core 754.

Ocular implant 100 extends along a generally curved longitudinal axis2134. Longitudinal axis 2134 defines a first plane 2154. In theembodiment of FIG. 22, the flexibility of ocular implant 100 is at amaximum when it is bending along first plane 2154, and implant 100 hasless flexibility when bending along a plane other than first plane 2154(e.g., a plane that intersects first plane 2154). Accordingly, firstplane 2154 may be generally referred to as a plane of preferentialbending.

Cannula 2108 of FIG. 22 comprises a generally tubular member 2162 havinga central axis 2164. Generally tubular member 2162 of FIG. 22 comprisesa proximal portion 2166, a distal end 2168, and a distal portion 2170extending between distal end 2168 and proximal portion 2166. In theexemplary embodiment of FIG. 22, proximal portion 2166 of cannula 2108is substantially straight.

In the embodiment of FIG. 22, central axis 2164 of cannula 2108 iscoaxial with the longitudinal axis 2134 of ocular implant 100. Withreference to FIG. 22, it will be appreciated that distal portion 2170 ofcannula 2108 is curved so that central axis 2164 of cannula 2108 definesa curvature plane 2172. Curvature plane 2172 may be referred to as aplane of curvature. With reference to FIG. 22, it will be appreciatedthat curvature plane 2172 divides cannula 2108 into a first portion anda second portion PB. Only second portion PB of cannula 2108 is shown inthe illustrative embodiment of FIG. 22. In this embodiment, curvatureplane 2172 is coincident with first plane 2154.

FIG. 23 is an additional perspective view of assembly 2182 shown in theprevious figure. In FIG. 23, core 754 of the delivery system'sadvancement mechanism and ocular implant 100 are shown extending throughdistal port 2188 of cannula 2108. With reference to the previous figure,it will be appreciated that core 754 and ocular implant 100 have beenmoved in a distal direction relative to the position of those elementsshown previously. Schlemm's canal SC of an eye is illustrated usingdashed lines in FIG. 23. In the embodiment of FIG. 23, a portion ofocular implant 100 has been advanced into Schlemm's canal SC. Ocularimplant 100 is oriented so as to bend most easily in a directionconforming with the natural curvature of Schlemm's canal SC. In FIG. 23,a distal end of a push tube PT of the delivery system's advancementmechanism is shown contacting a proximal end of ocular implant 100. Inthe embodiment of FIG. 23, push tube PT is disposed in the lumen definedby cannula 2108.

FIG. 24 is an additional perspective view showing ocular implant 100 andcannula 2108 shown in the previous figure. With reference to FIG. 24, itwill be appreciated that ocular implant 100 has been advanced to aposition outside of cannula 2108. After advancing ocular implant 100into Schlemm's canal, the core and the push tube have been retractedinto lumen 2184 defined by cannula 2108.

With reference to the figures described above, it will be appreciatedthat methods in accordance with the present detailed description may beused to position a distal portion of an implant in Schlemm's canal of aneye. An exemplary method in accordance with the present detaileddescription may include the step of advancing a distal end of a cannulathrough a cornea of the eye so that a distal portion of the cannula isdisposed in the anterior chamber of the eye. The cannula may be used toaccess Schlemm's canal, for example, by piercing the wall of Schlemm'scanal with a distal portion of the cannula.

Methods in accordance with the present detailed description can be usedto deliver an implant into Schlemm's canal of an eye. In these exemplarymethods, a distal portion of the ocular implant may be advanced out ofthe distal port of a cannula and into Schlemm's canal. Ocular implant100 may be disposed on a core while the distal portion of the implant isadvanced into Schlemm's canal. In some useful methods, the ocularimplant comprises a body defining a plurality of apertures and themethod includes the step of closing the apertures with a core. When thisis the case, the distal portion of the ocular implant may be advancedinto Schlemm's canal while the apertures are closed by the core. Closingthe apertures as the ocular implant is advanced into Schlemm's canal mayreduce the trauma inflicted on Schlemm's canal by the procedure. Oncethe ocular implant has reached a desired position, the core may beretracted while a push tube prevents ocular implant from being pulledproximally.

FIG. 25A is a cross sectional view of cannula 2108 sectioned alongcutting line A-A shown in FIG. 25C. FIG. 25B is an axial plan viewcreated from the viewpoint illustrated by line B-B in FIG. 25C. FIG. 25Cis a plan view showing cannula 2108. FIG. 25A, FIG. 25B, and FIG. 25Cmay be collectively referred to as FIG. 25.

With reference to FIG. 25, it will be appreciated that cannula 2108comprises a generally tubular member 2162 having a central axis 2164. Inthe embodiment of FIG. 25, generally tubular member 2162 comprises aproximal portion 2166, a distal end 2168, and a distal portion 2170extending between distal end 2168 and proximal portion 2166. In theexemplary embodiment of FIG. 25, proximal portion 2166 is substantiallystraight, and distal portion 2170 is curved. A distal opening 2169 anddistal opening surface 2167 form a tongue 2190. Distal opening 2169fluidly communicates with a lumen 2184 defined by generally tubularmember 2162. With reference to FIG. 25, it will be appreciated thatdistal portion 2170 is curved in the plane of FIG. 25A and curved in theplane of FIG. 25B.

FIGS. 26 and 27 provide additional views of cannula 2108. Distal openingsurface 2167 in tongue 2190 has two sections: a first section 2191 lyingin a plane that forms a first section angle greater than 0 degrees andless than 90 degrees with respect to longitudinal axis 2164 of thecannula tube 2162 and a notched section 2192 whose angle with respect toaxis 2164 varies from an angle less than that of the first section to anangle greater than the first section.

FIG. 28 is a schematic illustration of the use of a ocular implantdelivery system cannula. As the distal tip 2168 passes through thetrabecular meshwork 36 of the human subject's eye and into Schlemm'scanal 38, the distal opening surface of first and second sections 2191and 2192 of tongue portion 2190 depresses the meshwork and Schlemm'scanal tissue in a tenting area 37 to form a transition area for deliveryof an ocular implant into Schlemm's canal. As shown, not all of thedistal opening of the cannula has been inserted into Schlemm's canal.Instead, tongue 2190 causes the subject's tissue to form a ramp that,together with the inner surface of tongue 2190, guides insertion of theocular implant into Schlemm's canal.

In addition, since the curve of the cannula at the distal tip 2168 isgreater than the curve of Schlemm's canal (i.e., the cannula at itsdistal end has a smaller radius of curvature than Schlemm's canal), thedistal tip may be oriented so that the ocular implant is delivered intothe center or possibly slightly radially inward of the outer wall ofSchlemm's canal. This combination of cannula shape and cannulaorientation helps guide the ocular implant safely into Schlemm's canal.

FIGS. 29 and 30 show yet another embodiment of a cannula tube 2962 foruse in an ocular implant delivery system. In this embodiment, a tongueregion 2990 extending proximally from the distal tip 2968 of the cannulais defined by a distal opening 2169 and a distal opening surface 2167with a complex shape. Tube 2962 is formed as a curved cylinder whichdefines a cylindrical envelope. Tongue 2990 can be described as a regionin which the angular extent of material coverage within the cylindricalenvelope increases from the distal tip 2968 proximally to a first point2901, then decreases from point 2901 proximally to a second point 2902,then once again increases from point 2902 proximally to complete 360degree material coverage within the cylindrical envelope at point 2903.

FIGS. 31-35 show an ocular implant 900 being delivered through a yetanother embodiment of an ocular implant delivery system cannula 3102into Schlemm's canal 38. (Schlemm's canal is shown in these figures asbeing straight instead of curved for ease of illustration.) The ocularimplant shown is described in more detail in U.S. Ser. No. 11/860,318,“Ocular Implants,” filed Sep. 24, 2007. It should be understood thatother ocular implants may be delivered and deployed by the deliverysystem of this invention.

As shown in FIG. 31, a distal portion of cannula 3102 has passed throughthe cornea to be within the anterior chamber 37 of the eye and haspierced the trabecular meshwork 36 to enable a distal opening 3108 ofcannula 3102 to communicate with Schlemm's canal 38. In this embodiment,cannula 3102 is a rigid curved tube that has a cutting portion 3110 atthe distal opening 3108, as shown in more detail in FIGS. 32 and 33. Insome embodiments, cannula 3102 is curved to achieve tangential entryinto Schlemm's canal, such as by forming an arc of a circle having aradius of curvature less than about 0.1 inches. Other embodiments mayhave other shapes and curves.

In this embodiment, cutting portion 3110 is formed from two convex edges3112 meeting at a tip 3114. In other embodiments, the cutting edges canbe concave or straight. As shown, edges 3112 extend from tip 3114 to apair of optional stops 3116 formed at the intersection of edges 3112with an optional cannula extension portion 3118. As shown in FIG. 31,the distal end of cannula 3102 may be advanced within the anteriorchamber 37 toward the trabecular meshwork 36. When the distal end ofcannula 3102 meets the trabecular meshwork, tip 3114 and edges 3112 ofcutting portion 3110 are advanced to extend through the trabecularmeshwork into Schlemm's canal while a tongue or extension portion 3118bends back and remains within the anterior chamber 37. Distal movementof cannula 3102 ceases when stops 3116 engage the trabecular meshwork.

In some embodiments, cannula 3102 is formed from transparentpolycarbonate tubing having a diameter less than about 0.030 inches,e.g., an outer diameter of 0.028 inches and an inner diameter of 0.014inches. In embodiments with cutting edges leading to stops, the cuttingedges may be at angles of between about 10 degrees and 80 degrees withrespect to the cannula's central axis, and the stops may be locatedapproximately one-half diameter inward of tip 3114. In embodiments witha cannula extension portion, the extension portion 3118 may extendapproximately 1.5 mm beyond tip 3114. Among other functions, the bendingof tongue or extension portion 3118 while forward pressure is maintainedon the cannula (as shown, e.g., in FIG. 31) provides feedback to theuser of robust engagement with the trabecular meshwork and accuratepositioning of the distal end of the cannula.

During delivery, ocular implant 900 is mounted on a core or carrier 754which is movable with implant 000 within cannula 3102. Among otherfunctions, one particular function of core 754 is to block the openings3122 formed in implant 900 so as to minimize interference between theimplant and tissue within Schlemm's canal 38 as the implant is advanced.The ocular implant 900 has a blunt distal end 902 in this embodiment toavoid damage to ocular tissue. In other embodiments, the blunt distalend may be provided at least in part by the carrier.

FIGS. 36A and 36B are section views illustrating an exemplary method inaccordance with the present detailed description. The picture plane ofFIG. 36A extends laterally across Schlemm's canal SC and the trabecularmeshwork 596 overlaying Schlemm's canal SC. In the embodiment of FIG.36A, the distal end 501 of a cannula 502 has been positioned proximateSchlemm's canal SC. An exemplary method in accordance with the presentdetailed description may include the step of advancing the distal end ofcannula 502 through the cornea of an eye so that a distal portion ofcannula 502 is disposed in the anterior chamber 594 of the eye.

FIG. 36B is an additional section view showing Schlemm's canal SC shownin the previous figure. In FIG. 36, a distal end 501 of cannula 502 isshown extending through a wall of Schlemm's canal SC and trabecularmeshwork 596. A distal opening 504 of cannula 502 fluidly communicateswith Schlemm's canal in the embodiment of FIG. 36B.

While exemplary embodiments of the present invention have been shown anddescribed, modifications may be made, and it is therefore intended inthe appended claims to cover all such changes and modifications whichfall within the true spirit and scope of the invention.

1. A cannula for an ocular implant delivery system comprising: a tubularmember comprising a curved portion, a distal opening surrounded by adistal opening surface, and a distal tip, the distal tip being adaptedto be inserted into an anterior chamber of a human subject's eye,through trabecular meshwork and into Schlemm's canal of the eye, aproximal portion of the tubular member being adapted to extend from alocation exterior to the eye when the distal tip is in Schlemm's canalof the eye, the cannula being further adapted to cooperate with anadvancement mechanism to advance an ocular implant through the tubularmember toward and through the distal opening into Schlemm's canal of theeye when the distal tip is disposed in Schlemm's canal.
 2. The cannulaof claim 1 wherein the tubular member further comprises a tongue regionextending proximally from the distal tip on one side of the tubularmember, the tongue region forming at least part of the distal openingsurface.
 3. The cannula of claim 2 wherein the distal opening surfaceextends solely proximally from the distal tip.
 4. The cannula of claim 3wherein the distal opening surface is disposed in a distal openingplane.
 5. The cannula of claim 4 wherein the tubular member curvedportion defines a curve plane, and the distal opening plane is at anangle other than 90 degrees with respect to the curve plane.
 6. Thecannula of claim 3 wherein the distal opening surface comprises a firstsection disposed in a distal opening plane disposed at a first sectionangle between 0 degrees and 90 degrees with respect to a longitudinalaxis of the tubular member at the distal opening and a second sectionwhose angle with respect to the longitudinal axis of the tubular membervaries from an angle less than the first section angle at a distal limitof the second section to an angle greater than the first section angleat a proximal limit of the second section.
 7. The cannula of claim 3wherein the distal opening surface comprises an edge formed from acircumferential portion of a cylindrical envelope defined by the tubularmember, the angular extent of the circumferential portion within thecylindrical envelope increasing from the distal tip proximally to afirst point, the angular extent of the circumferential portion withinthe cylindrical envelope decreasing between the first point and a secondpoint proximal to the first point, the angular extent of thecircumferential portion within the cylindrical envelope increasing to360 degrees between the second point and a third point proximal to thesecond point.
 8. The cannula of claim 2 wherein the tubular memberfurther comprises a second tongue region and a stop member defining thedistal opening surface.
 9. The cannula of claim 1 wherein an externaldiameter of the tubular member at a distal end of the tubular member isless than an external diameter of the tubular member proximal to thedistal opening.
 10. The cannula of claim 1 wherein the curved portion ofthe tubular member has a bend angle between 105 degrees and 165 degrees.11. An ocular implant system comprising: an ocular implant comprising aninlet sized and configured to be disposed in an anterior chamber of ahuman subject's eye and a body sized and configured to be disposed inSchlemm's canal of the eye, the ocular implant being adapted to bendpreferentially in a preferential bending plane; and a delivery cannulacomprising a tubular member comprising a curved portion, a distalopening surrounded by a distal opening surface, and a distal tip, thedistal tip being adapted to be inserted into an anterior chamber of ahuman subject's eye, through trabecular meshwork and into Schlemm'scanal of the eye, the tubular member being adapted to extend from alocation exterior to the eye when the distal tip is in Schlemm's canalof the eye, the cannula being further adapted to cooperate with anadvancement mechanism to advance the ocular implant through at least thecurved portion of the tubular member toward and through the distalopening into Schlemm's canal of the eye when the distal tip of thedelivery tool is disposed in Schlemm's canal.
 12. The ocular implantsystem of claim 11 wherein a central axis of the cannula defines acannula curvature plane, the ocular implant being oriented within thecannula so that the implant preferential bending plane is co-planar withthe cannula curvature plane.
 13. A method of deploying an ocular implantinto Schlemm's canal of a human eye comprising: inserting a distal tipof a delivery tool within an anterior chamber of the eye throughtrabecular meshwork of the eye into Schlemm's canal of the eye; andadvancing an ocular implant through a curved portion and a distalopening of the delivery tool to place a body portion of the ocularimplant in Schlemm's canal and an inlet portion of the ocular implant inthe anterior chamber.
 14. The method of claim 13 wherein the deliverytool comprises a curved distal portion, the inserting step comprisingaligning the curved distal portion with respect to Schlemm's canal sothat the ocular implant is delivered into the center of Schlemm's canalor slightly radially inward of an outer wall of Schlemm's canal.
 15. Themethod of claim 14 wherein the curved distal portion of the deliverytool has a radius of curvature smaller than a radius of curvature ofSchlemm's canal.
 16. The method of claim 13 wherein the inserting stepcomprises advancing the distal tip into Schlemm's canal until a stopportion of a distal opening surface surrounding the distal openingengages the trabecular meshwork.
 17. The method of claim 13 wherein theinserting step comprises depressing trabecular meshwork and Schlemm'scanal tissue with the distal tip with a distal opening surfacesurrounding the distal opening, the distal opening surface beingdisposed at an angle other than 90 degrees with respect to alongitudinal axis of the delivery tool.
 18. The method of claim 13wherein the delivery tool comprises a distal opening surface surroundingthe distal opening, the inserting step comprising inserting less thanall of the distal opening surface into Schlemm's canal.
 19. The methodof claim 13 wherein the delivery tool comprises a distal opening surfacesurrounding the distal opening and the distal tip is disposed at thedistal end of a tongue, the inserting step comprising inserting thetongue into Schlemm's canal.
 20. The method of claim 19 wherein theadvancing step comprises advancing the ocular implant through the distalopening while a portion of the distal opening surface is disposed inSchlemm's canal and a portion of the distal opening surface is disposedoutside of Schlemm's canal.